This application claims priority to Korean patent applications number 10-2010-0038326 filed on Apr. 26, 2010 and Korean patent application number 10-2011-0009541 filed on January 31 by the same application as the present application, which are incorporated herein by reference in their entirety.
As a universal method for a user authentication, a password authentication method is widely used. In the password authentication method, a password inputted from a user at the time of an initial setting procedure is stored, and a security password inputted from a user, if necessary, is compared with a previously stored password. When matched, the authentication of the password is succeeded.
Here, the password might be exposed to other in various ways. For example, a third party might be watch a users password being inputted, thus knowing the password. A certain hacking program might be programmed to hack the password key-inputted on a user's terminal, thus knowing the password. The hacking program might intercept a password from the data in a network communication, thus knowing the password.
As explained above, the password input method is configured to ask the user to input the same password that the user initially has set, so if a third party finds out the password, the third party can use the password limitlessly. Even when the password inputted from the user is encoded for reinforcing the security, the third party might hack the encoding method adapted to the password, thus unlocking the password. So, it is urgently needed to develop a new password authentication method which makes sure that the third party cannot use the password even when the user's password is exposed to the third part.